18720123 has 4 divisors (see below), whose sum is σ = 24960168. Its totient is φ = 12480080.

The previous prime is 18720083. The next prime is 18720173. The reversal of 18720123 is 32102781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32102781 = 3 ⋅10700927.

It is a cyclic number.

It is not a de Polignac number, because 18720123 - 2²⁰ = 17671547 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18720093 and 18720102.

It is not an unprimeable number, because it can be changed into a prime (18720173) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3120018 + ... + 3120023.

It is an arithmetic number, because the mean of its divisors is an integer number (6240042).

Almost surely, 2^18720123 is an apocalyptic number.

18720123 is a deficient number, since it is larger than the sum of its proper divisors (6240045).

18720123 is an equidigital number, since it uses as much as digits as its factorization.

18720123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6240044.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 18720123 is about 4326.6757447260. The cubic root of 18720123 is about 265.5234603916.

The spelling of 18720123 in words is "eighteen million, seven hundred twenty thousand, one hundred twenty-three".